In Winter, an Oasis of Warmth and Light

College’s Greenhouses Grow all Year Long

Greenhouse assistant Theresa Barry re-pots an orchid in the Murdough Greenhouses on the roof of Dartmouth College’s new Life Sciences building. There are over 1,000 orchids in their collection. (Valley News - James M. Patterson) Purchase photo reprints »

Daniel Calano, a pre-med student from Eastchester, N.Y., studies over lunch in a visiting room of the Murdough Greenhouses. Calano discovered the greenhouse during a drawing class that used the plants as subjects. “Before that, I never knew this place existed,” he said. “I thought of it as a really cool place, especially in the winter because it had the sun lamps.” (Valley News - James M. Patterson) Purchase photo reprints »

Tucked into a corner of the tropical orchid room at the Murdough Greenhouses at Dartmouth College is a specimen of one of the most valued commodities in the world.

The only orchid grown commercially for human consumption, it’s a lanky vine with elongated, droopy chartreuse leaves that climbs the wall like a bean stalk. Unlike the other orchids in the room, with luminescent flowers of every hue, it’s not particularly showy, and it’s possible to walk right by it unless it’s pointed out to you. But after it flowers, it grows the long black pods whose seeds and flesh are used to make vanilla extract, which can command high prices on the world market.

Vanilla planifolia, or flat-leafed vanilla, is just one of hundreds of specimens of tropical, sub-tropical, aquatic and desert, or xeric, plants on public view in the Murdough greenhouses. They are also home to an extensive orchid collection, numbering about 1,000, donated by alumnus Alan Brout that has been recognized by the American Orchid Society for its significance. The orchids and other specimens total around 1,500, said greenhouse manager Kim DeLong.

The greenhouses, said DeLong, are there for “the education of the public and to support classes here at Dartmouth.”

When the greenhouses moved 15 months ago to their new location atop the Class of 1978 Life Sciences Building, a quarter-mile north of the Dartmouth green, the space doubled from 3,000 to 6,000 square feet, expanding the areas devoted to both public exhibition and research, DeLong said. The temperatures range between 75 and 80 degrees during the day, and 50 and 45 degrees at night for the tropical and subtropical rooms, respectively, said DeLong. The same temperatures hold, approximately, for the orchid rooms.

During the dreariest days of winter, the greenhouses draw visitors craving warmth and the vibrant colors of living things. Some of the specimens are rare, some common; some have medicinal or commercial applications; some are prized for their beauty, some for their ugliness; and all are marvels of adaptation to climates that can be rigorous, prime examples of the old saw that nature abhors a vacuum.

In northern New England, of course, none of these tropical or desert plants are found naturally, which gives even such a relatively mundane specimen as an orange tree a tinge of exoticism. But then there are the specimens that seem otherwordly, like the living rock, an African succulent that looks more like a stone than a plant, and Huperzia goebellii, some of the most primitive plants on earth, so ancient they date to 300 million years ago.

There is the sensitive plant, whose small, delicate leaves contract when you touch them; a range of carnivorous plants that, because they grow in nutrient-poor soil in their native habitats, have adapted to trap insects for food; and such trees and bushes as coffee, chocolate, banana, lemon, orange, pomegranate, cinnamon, tea and guava.

If you nibble a leaf from the miracle plant and then taste a lemon, it makes the citrus taste sweet, not sour. And there’s khat, the plant native to the Horn of Africa and the Arabian Peninsula that is known for its stimulant qualities and which is chewed like tobacco. (At the invitation of DeLong, I ate one leaf, felt nothing, and assumed I was khat-proof until, three minutes later, a not-entirely-pleasant feeling of tingling light-headedness kicked in (Kids, don’t try this at home).

Only two people staff the greenhouses, Kim DeLong and Theresa Barry. They are responsible for the care and feeding of the plants, which entails watering, pruning, repotting and pest control.

“I don’t know how pests come in but somehow they get in,” DeLong said. “You think you’ve got it under control but all of a sudden they show up.”

To combat such scourges as aphids, scale, thrips, mealybugs and whiteflys, which can lay waste to plants, DeLong and Barry use biological controls, rather than pesticides. By introducing such beneficial insects or parasites as lacewings and ladybugs and delphastus, which are natural predators, they check the growth of unwelcome insects. Biological control is a strategy increasingly in use, DeLong said, because “more and more commercial growers realize pesticides don’t cut it” due to the build-up of resistance to them by insects.

DeLong has been manager for a year. Prior to being hired by Dartmouth, she worked for seven years at the University of California, Berkeley as a greenhouse manager and instructional plant collector. This was a mid-career switch for her, one that required her to study horticulture, plant propagation and plant pathology, as well as mastering the complex botanical nomenclature of such plants as Burbidgea scheizocheila (Golden Brush) or Ludisia Discolor, the Jewel orchid, which is noted for its variegated foliage.

“Learning the botanical names is kind of like learning a foreign language,” DeLong said.

For scientist and Dartmouth professor Rebecca Irwin, the greenhouses are an integral part of her work, both as a researcher and teacher. She teaches a course in plant biology, she wrote in an email, “that covers plant diversity and plant form and function. The course would be impossible to teach without the greenhouse collection. The students love working in the greenhouse and studying plant diversity. Many don’t have much experience with plants, and so it is a real eye-opener.”

The greenhouses welcome visitors Monday through Friday from 8:30 a.m. until 4 p.m. There is no admission charge. The Class of 1978 Life Sciences Building is at the corner of College Street and Dewey Field Road in Hanover.